Research Article |
Corresponding author: Shuang-Hui He ( heshuanghui@bjfu.edu.cn ) Academic editor: María P. Martín
© 2023 Yue Li, Wei-Qi Xu, Shi-Liang Liu, Ning Yang, Shuang-Hui He.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Li Y, Xu W-Q, Liu S-L, Yang N, He S-H (2023) Species diversity and taxonomy of Scytinostroma sensu stricto (Russulales, Basidiomycota) with descriptions of four new species from China. MycoKeys 98: 133-152. https://doi.org/10.3897/mycokeys.98.105632
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Scytinostroma is species-rich genus in Peniophoraceae, Russulales and has been shown to be polyphyletic. In this study, we performed phylogenetic analyses on the core clade of Scytinostroma based on concatenated ITS1-5.8S-ITS2-nrLSU sequence data. Fifteen lineages including four new species from China, Scytinostroma beijingensis, S. boidinii, S. subduriusculum, and S. subrenisporum, were recognized. The genus Michenera was nested within the Scytinostroma s.s. clade in the phylogenetic tree of Peniophoraceae. Sequences of S. portentosum (type species) and S. hemidichophyticum from Europe formed a strongly supported lineage sister to the S. portentosum sample from Canada. It is supposed that the European “S. portentosum” is S. hemidichophyticum, and the former species is restricted in distribution to North America. Scytinostroma duriusculum is supposed to be a species complex. Samples from Sri Lanka (the type locality) formed a lineage sister to those from China, Thailand and Vietnam (described herein as S. subduriusculum) and two samples from France that might represent an undescribed species. The four new species are described and illustrated, and an identification key to all the 14 Scytinostroma s.s. species worldwide is provided. Until now, seven species of Scytinostroma s.s. have been found in China. Our results increased the knowledge of species diversity and taxonomy of corticioid fungi in China.
corticioid fungi, Peniophoraceae, phylogeny, white rot, wood-decaying fungi
The genus Scytinostroma Donk sensu lato (Peniophoraceae, Russulales), typified by S. portentosum (Berk. & M.A. Curtis) Donk, is characterized by resupinate, effused basidiomes with a smooth to tuberculate hymenophore, a dimitic hyphal system with dextrinoid and cyanophilous skeletal hyphae, presence of gloeocystidia in most species, and subglobose to ellipsoid, variably amyloid or inamyloid, smooth basidiospores (
In situ photos of specimens were taken with a Canon camera EOS 70D (Canon Corporation, Japan). Specimens were dried with a portable dryer, labelled, and then stored in a freezer at minus 40 °C for two weeks to kill the insects and their eggs before proceeding with morphological and molecular studies. Voucher specimens are deposited at the herbarium of
Beijing Forestry University, Beijing, China (
Thin, freehand sections were made from dried basidiomes and mounted in 2% (weight/volume) aqueous potassium hydroxide (KOH) and 1% (w/v) aqueous phloxine. Amyloidity and dextrinoidity of hyphae and basidiospores were checked in Melzer’s reagent (IKI). Cyanophily of hyphal and basidiospore walls were observed in 1% (w/v) cotton blue in 60% (w/v) lactic acid (CB). Microscopic examinations were carried out with a Nikon Eclipse 80i microscope (Nikon Corporation, Japan) at magnifications up to 1000×. Drawings were made with the aid of a drawing tube. The following abbreviations are used: IKI– = neither amyloid nor dextrinoid, CB+ = cyanophilous, CB– = acyanophilous, SA+ = positive reaction in Sulphobenzaldehyde, SA– = negative reaction in Sulphobenzaldehyde, L = mean spore length, W = mean spore width, Q = L/W ratio, n (a/b) = number of spores (a) measured from the number of specimens (b). Color codes and names follow
A CTAB plant genomic DNA extraction kit, DN14 (Aidlab Biotechnologies Co., Ltd., Beijing, China) was used to extract total genomic DNA from dried specimens, then amplified by the polymerase chain reaction (PCR), according to the manufacturer’s instructions. The ITS1-5.8S-ITS2 region was amplified with the primer pair ITS5/ITS4 (
The dataset of concatenated ITS1-5.8S-ITS2-nrLSU sequences of the Peniophoraceae was analyzed. Amylostereum chailletii (Pers.) Boidin and A. laevigatum (Fr.) Boidin were selected as the outgroup (
Maximum likelihood (ML) analyses, and Bayesian inference (BI) were carried out by using RAxML v.8.2.10 (
The concatenated ITS1-5.8S-ITS2-nrLSU dataset contained 58 ITS and 52 nrLSU sequences from 61 samples, representing 33 ingroup taxa and the outgroup (Table
Species and sequences used in the phylogenetic analyses. New species are set in bold with type specimens indicated with an asterisk (*).
Species | Specimen No. | Locality | GenBank Accession No. | Reference | |
---|---|---|---|---|---|
ITS | nrLSU | ||||
Asterostroma laxum | EL33-99 | Estonia | AF506410 | AF506410 |
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Asterostroma muscicola | KHL9537 | Puerto Rico | AF506409 | AF506409 |
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Baltazaria galactina | CBS 752.86 | France | MH862034 | MH873721 |
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Baltazaria neogalactina | CBS 755.86 | French Guiana | MH862037 | MH873724 |
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Confertobasidium olivaceoalbum | FP 90196 | USA | AF511648 | AF511648 |
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Dichostereum durum | CBS 707.81 | France | MH861450 | MH873192 |
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Dichostereum effuscatum | GG930915 | France | AF506390 | AF506390 |
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Gloiothele lactescens | EL8-98 | Sweden | AF506453 | AF506453 |
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Gloiothele lamellosa | KHL11031 | Venezuela | AF506454 | AF506454 |
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Lachnocladium schweinfurthianum | KM49740 | Cameroon | MH260033 | MH260051 |
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Lachnocladium sp. | KHL10556 | Jamaica | AF506461 | AF506461 |
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Metulodontia nivea | NH 13108 | Russia | AF506423 | AF506423 |
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Peniophora quercina | CBS 407.50 | France | MH856687 | MH868204 |
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Peniophora tristicula | He 4775 | China | MH669235 | MH669239 |
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Peniophora versiformis | He 3029 | China | MK588756 | MK588796 |
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Scytinostroma acystidiatum | He 5646 | China | MK625568 | MK625494 | Present study |
Scytinostroma acystidiatum | He 5668 | China | MK625569 | MK625496 | Present study |
Scytinostroma alutum | CBS 762.81 | France | MH861482 | MH873221 |
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Scytinostroma alutum | CBS 763.81 | France | MH861483 | MH873222 |
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Scytinostroma artocreas | GHL-2016-Oct | USA | MH142900 | MH204691 |
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Scytinostroma beijingensis | He 7203 | China | – | OQ729729 | Present study |
Scytinostroma beijingensis | He 7668 | China | – | OQ729730 | Present study |
Scytinostroma beijingensis | He 7768* | China | OQ731943 | OQ729731 | Present study |
Scytinostroma boidinii | He 2499 | China | MK625573 | – | Present study |
Scytinostroma boidinii | He 5138 | China | MK625572 | MK625497 | Present study |
Scytinostroma boidinii | He 6911* | China | OQ731934 | OQ729724 | Present study |
Scytinostroma boidinii | He 7465a | China | OQ731935 | – | Present study |
Scytinostroma boidinii | He 7465b | China | OQ731936 | – | Present study |
Scytinostroma caudisporum | CBS 746.86 | Gabon | MH862030 | AY293210 |
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Scytinostroma duriusculum | He 5748 | Sri Lanka | OQ865248 | – | Present study |
Scytinostroma duriusculum | He 5756 | Sri Lanka | OQ865249 | – | Present study |
‘Scytinostroma duriusculum’ | CBS 757.81 | France | MH861477 | MH873216 |
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‘Scytinostroma duriusculum’ | CBS 758.81 | France | MH861478 | MH873217 |
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Scytinostroma hemidichophyticum | CBS 702.84 | Belgium | MH861818 | MH873509 |
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Scytinostroma hemidichophyticum | CBS 759.81 | France | MH861479 | MH873218 |
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Scytinostroma hemidichophyticum | CBS 760.81 | France | MH861480 | MH873219 |
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Scytinostroma incrustatum | He 2841 | China | MH142906 | MH142910 |
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Scytinostroma incrustatum | He 5368 | China | MH204689 | MH204690 |
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Scytinostroma portentosum | CBS 503.48 | Canada | MH856447 | AF518723 |
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Scytinostroma portentosum | EL11-99 | Sweden | AF506470 | AF506470 |
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Scytinostroma portentosum | GEL3225 | – | – | AJ406488 |
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Scytinostroma renisporum | CBS 771.86 | Indonesia | MH862051 | MH873738 |
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Scytinostroma renisporum | CBS 772.86 | Indonesia | MH862052 | MH873739 |
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Scytinostroma subduriusculum | He 3590 | China | MK625571 | MK625499 | Present study |
Scytinostroma subduriusculum | He 4146 | Thailand | MK625570 | MK625498 | Present study |
Scytinostroma subduriusculum | He 7134 | China | OQ731937 | – | Present study |
Scytinostroma subduriusculum | He 7141 | China | OQ731938 | OQ729725 | Present study |
Scytinostroma subduriusculum | He 7148 | China | OQ731939 | – | Present study |
Scytinostroma subduriusculum | He 7150 | China | OQ731940 | OQ729726 | Present study |
Scytinostroma subduriusculum | He 7657* | China | OQ731941 | OQ729727 | Present study |
Scytinostroma subduriusculum | He 7717 | China | OQ731942 | OQ729728 | Present study |
Scytinostroma subrenisporum | He 4384 | China | MK625567 | MK625495 | Present study |
Scytinostroma subrenisporum | He 4792* | China | MK625566 | MK625493 | Present study |
Scytinostroma yunnanense | CLZhao 10802 | China | MT611446 | – |
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Scytinostroma yunnanense | CLZhao 11010 | China | MT611447 | – |
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Vararia amphithallica | He 4330 | China | MK674474 | MK625542 | Present study |
Vararia investiens | TAA164122 | Norway | AF506484 | AF506484 |
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Vesiculomyces citrinus | He 3716 | China | KY860369 | KY860429 | Present study |
Vesiculomyces citrinus | EL53-97 | Sweden | AF506486 | AF506486 |
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OUTGROUP | |||||
Amylostereum chailletii | NH 8031 | Sweden | AF506406 | AF506406 |
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Amylostereum laevigatum | NH 12863 | Sweden | AF506407 | AF506407 |
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In the tree, Scytinostroma s.s. clade received a moderately strong support value in ML analysis (bootstrap value = 56) but a strong value in BI (Bayesian posterior probabilities = 1). Four new distinct lineages corresponding to Scytinostroma beijingensis, S. boidinii, S. subduriusculum and S. subrenisporum spp. nov. were recognized. Sequences of S. portentosum and S. hemidichophyticum from Europe formed a strongly supported lineage sister to the S. portentosum sample from Canada. Samples of S. duriusculum from France and those from Sri Lanka (the type locality) formed a lineage sister to S. subduriusculum. Scytinostroma incrustatum (S.H. He, S.L. Liu & Nakasone) K.H. Larss. and S. artocreas (Berk. & M.A. Curtis) K.H. Larss.,which were formerly placed in Michenera, were nested within Scytinostroma s.s. clade.
China, Beijing, Haidian District, Yangtaishan Forest Park, on dead Pyrus tree, 4 September 2022, He 7768 (
Refers to the type locality in Beijing, China.
Basidiomes annual, resupinate, widely effused, closely adnate, inseparable from substrate, coriaceous, first as small patches, later confluent up to 12 cm long, 4.5 cm wide, up to 200 µm thick in section. Hymenophore smooth, greyish yellow (4B5) to greyish orange (5B5), unchanged in KOH, not cracked or deeply cracked with age; margin thinning out, adnate, fimbriate, white or concolorous with hymenophore surface. Context yellow.
Hyphal system dimitic. Context thickening, compact. Generative hyphae rare, scattered, simple-septate, colorless, thin-walled, 2–3 µm in diam., IKI–, CB–. Skeletal hyphae dominant, colorless to yellow, distinctly thick-walled, moderately branched, 2.5–4 µm in diam., weakly dextriniod, CB+. Catahymenium composed of skeletal hyphae, gloeocystidia, basidia and basidioles. Skeletal hyphae abundant, similar to those in the context, but strongly dextrinoid, frequently dichotomous-branched with acute tips, 1–2 µm wide at lowest part. Gloeocystidia abundant, SA+, with two shapes (1) ventricose, colorless, thin- to slightly thick-walled, mostly embedded, usually with contents, 28–40 × 8–15 µm; (2) subcylindrical, colorless, thin- to slightly thick-walled, mostly projecting beyond the hymenium, usually with contents, 45–65 × 5–7 µm. Basidia subcylindrical, slightly curved, thin-walled, colorless, smooth, with four sterigmata and a basal simple septum, 30–36 × 4.5–6.5 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores subglobose, with a distinct apiculus, thin-walled, colorless, smooth, occasionally with oil-drops, amyloid, CB–, 5.5–6.5 (–6.8) × (5–) 5.2–6.2 (–6.5) µm, L = 5.9 µm, W = 5.8 µm, Q = 1.01–1.02 (n = 90/3).
China, Beijing, Haidian District, Jiufeng Forest Park, on dead Pyrus tree, 26 August 2022, He 7759 (
Scytinostroma beijingensis is characterized by having two kinds of gloeocystidia and short branched skeletal hyphae in hymenium, and growing on Pyrus. In the phylogenetic tree (Fig.
China, Beijing, Mentougou District, Xiaolongmen Forest Park, on dead angiosperm branch, 28 August 2020, He 6911 (
Named to honor Dr. Jacques Boidin (Lyon, France) who contributed much to the taxonomy of Scytinostroma.
Basidiomes annual, resupinate, widely effused, closely adnate, inseparable from substrate, membranaceous to coriaceous, first as small patches, later confluent up to 9 cm long, 3.5 cm wide, up to 300 µm thick in section. Hymenophore smooth, pale yellow (4A3), greyish yellow (4B4) to greyish orange [5B(3–4)], unchanged in KOH, not cracked; margin thinning out, adnate, fimbriate, white or concolorous with hymenophore surface. Context pale yellow.
Hyphal system dimitic. Context thickening, compact. Generative hyphae rare, scattered, simple-septate, colorless, slightly thick-walled, 2–3 µm in diam., IKI–, CB–. Skeletal hyphae dominant, colorless to yellow, distinctly thick-walled, moderately branched, 1.5–2 µm in diam., dextriniod, CB+. Catahymenium composed of skeletal hyphae, gloeocystidia, basidia and basidioles. Skeletal hyphae abundant, similar to those in the context, but strongly dextrinoid, dichotomous-branched with acute tips, 1–1.5 µm wide at lowest part. Gloeocystidia abundant, subcylindrical to subfusiform, colorless, slightly thick-walled, with or without contents, weakly SA+, 50–80 × 5–10 µm. Basidia subclavate to subcylindrical, thin-walled, colorless, smooth, with four sterigmata and a basal simple septum, 30–50 × 4–7 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores subglobose, with a distinct apiculus, thin-walled, colorless, smooth, occasionally with oil-drops, amyloid, CB–, (4.5–) 5–5.5 (–6.5) × (4–) 4.5–5.5 (–6.2) µm, L = 5.1 µm, W = 5.0 µm, Q = 1.02–1.04 (n = 60/2).
China, Beijing, Mentougou District, Lingshan Scenic Spot, on dead angiosperm branch, 10 April 2022, He 7465a (
Scytinostroma boidinii is characterized by the relatively long gloeocystidia and subglobose basidiospores. In the phylogenetic tree (Fig.
China, Beijing, Haidian District, Beijing Botanical Garden, on dead angiosperm branch, 15 July 2022, He 7657 (
Refers to the morphological similarity and close phylogenetic relationship with S. duriusculum.
Basidiomes annual, resupinate, widely effused, closely adnate, inseparable from substrate, membranaceous to coriaceous, first as small patches, later confluent up to 18 cm long, 3 cm wide, up to 160 µm thick in section. Hymenophore smooth, light yellow (4A4) to greyish orange (5B4), unchanged in KOH, not cracked; margin thinning out, adnate, fimbriate, white or concolorous with hymenophore surface. Context pale yellow.
Hyphal system dimitic. Context thickening, compact. Generative hyphae rare, scattered, simple-septate, colorless, thin-walled, 2–3 µm in diam., IKI–, CB–. Skeletal hyphae dominant, colorless to pale yellow, distinctly thick-walled, moderately branched, 2.5–4.5 µm in diam., dextriniod, CB+. Catahymenium composed of skeletal hyphae, gloeocystidia, basidia and basidioles. Skeletal hyphae abundant, similar to those in the context, but strongly dextrinoid, 1–1.5 µm in diam. Gloeocystidia abundant, subclavate to subcylindrical, colorless, thin-walled, usually with contents, SA+, 50–70 × 6–9 µm. Basidia subclavate to subcylindrical, slightly curved, thin-walled, colorless, smooth, with four sterigmata and a basal simple septum, 30–45 × 6–7.5 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores subglobose, with a distinct apiculus, thin-walled, colorless, smooth, occasionally with oil-drops, amyloid, CB–, (6–) 6.2–7 (–7.5) × (5.5–) 5.8–6.8 (–7) µm, L = 6.5 µm, W = 6.3 µm, Q = 1.01–1.04 (n = 90/3).
CHINA, Beijing, Changping District, Baiyanggou Scenic Spot, on dead angiosperm branch, 21 July 2021, He 7134 (
Scytinostroma subduriusculum is characterized by subcylindrical gloeocystidia, subglobose, relatively large basidiospores, and growth on both angiosperm and gymnosperm trees. It is widely distributed in China, and also found in Thailand and Vietnam. In the phylogenetic tree (Fig.
China, Guizhou Province, Libo County, Maolan Nature Reserve, on dead angiosperm branch, 11 July 2017, He 4792 (
Refers to the morphological similarity and close phylogenetic relationship with S. renisporum.
Basidiomes annual, resupinate, widely effused, closely adnate, inseparable from substrate, membranaceous to coriaceous, first as small patches, later confluent up to 10 cm long, 2.5 cm wide, up to 100 µm thick in section. Hymenophore smooth, pale orange (5A3), light orange (5A4) to greyish orange [5B(5–6)], unchanged in KOH, not cracked; margin thinning out, adnate, fimbriate, white or concolorous with hymenophore surface. Context pale yellow.
Hyphal system dimitic. Context thickening, compact. Generative hyphae rare, scattered, simple-septate, colorless, thin-walled, 2–3 µm in diam., IKI–, CB–. Skeletal hyphae dominant, colorless to yellow, distinctly thick-walled, moderately branched, 1.5–2 µm in diam., dextriniod, CB+. Catahymenium composed of skeletal hyphae, basidia and basidioles. Skeletal hyphae abundant, similar to those in the context, but strongly dextrinoid, moderately branched with acute tips, 1.5–2 µm wide at lowest part. Gloeocystidia absent. Basidia subcylindrical, slightly curved, thin-walled, colorless, smooth, with four sterigmata and a basal simple septum, 35–45 × 4.5–6.5 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores ellipsoid to reniform, with a distinct apiculus, thin-walled, colorless, smooth, amyloid, CB–, (5.5–) 6–6.5 (–7) × (3.8–) 4–5 (–5.5) µm, L = 6.2 µm, W = 4.4 µm, Q = 1.35–1.45 (n = 60/2).
China, Anhui Province, Qimen County, Guniujiang Nature Reserve, on dead angiosperm branch, 8 August 2013, He 1720 (
Scytinostroma subrenisporum is characterized by the absence of gloeocystidia and ellipsoid to reniform basidiospores. In the phylogenetic tree (Fig.
Previous studies showed that Scytinostroma is polyphyletic (
On the one hand, species in Scytinostroma s.s. clade have some common morphological characters, for example, simple-septate generative hyphae, and ovoid, reniform to subglobose basidiospores with amyloid reactions in Melzer’s reagent. However, this doesn’t mean species with inamyloid basidiospores could not belong to Scytinostroma s.s. On the other hand, the shape of skeletal hyphae, presence of gloeocystidia and encrusted cystidia, and size of basidiospores varies in different species. Based on our phylogenetic and morphological study results, we recognized 14 species of Scytinostroma s.s.worldwide. Until now, seven species have been reported from China, all of which were newly described in the present study and other recently published papers (
1 | Gloeocystidia absent | 2 |
– | Gloeocystidia present | 3 |
2 | Basidiospores > 6 µm long | S. subrenisporum |
– | Basidiospores < 6 µm long | S. acystidiatum |
3 | Basidiospores > 15 µm long | 4 |
– | Basidiospores < 15 µm long | 6 |
4 | Basidiospores fusiform to navicular | S. caudisporum |
– | Basidiospores subglobose to globose | 5 |
5 | Lamprocystidia present, basidiospores 17–22 × 16–21 µm | S. incrustatum |
– | Lamprocystidia absent, basidiospores 16–19 × 14–16 µm | S. artocreas |
6 | Basidiospores ovoid to reniform | S. renisporum |
– | Basidiospores subglobose | 7 |
7 | Distributed in subtropical and tropical areas | 8 |
– | Distributed in temperate areas | 10 |
8 | Gloeocystidia < 50 µm long | S. yunnanense |
– | Gloeocystidia > 50 µm long | 9 |
9 | Reported from Sri Lanka, basidia 20–25 µm long, basidiospores 6–6.5 × 5.5–6 µm | S. duriusculum |
– | Reported from China, Thailand, Vietnam, basidia 30–45 µm long, basidiospores 6.2–7 × 5.8–6.8 µm | S. subduriusculum |
10 | Reported from occidental countries | 11 |
– | Reported from China | 13 |
11 | North American species | S. portentosum |
– | European species | 12 |
12 | Skeletal hyphae in hymenium rarely branched | S. alutum |
– | Skeletal hyphae in hymenium dichotomously branched | S. hemidichophyticum |
13 | Gloeocystidia two kinds | S. beijingensis |
– | Gloeocystidia one kind | 14 |
14 | Basidiospores > 6 µm in diam. | S. subduriusculum |
– | Basidiospores < 6 µm in diam. | S. boidinii |
This study was supported by the National Natural Science Foundation of China (Nos. 32070005 & 32270014).
No conflict of interest was declared.
No ethical statement was reported.
National Natural Science Foundation of China.
Conceptualization, S.-H.H.; methodology, Y.L. and S.-H.H.; performing the experiment, Y.L., W.-Q.X. and N.Y.; formal analysis, Y.L. and W.-Q.X.; validation, Y.L., W.-Q.X., S.-L.L. and S.-H.H.; resources, S.-H.H.; writing—original draft preparation, Y.L. and S.-L.L.; writing—review and editing, S.-H.H.; visualization, Y.L.and S.-L.L.; supervision, S.-H.H.; project administration, S.-H.H.; funding acquisition, S.-H.H. All authors have read and agreed to the published version of the manuscript.
Yue Li https://orcid.org/0000-0003-4091-1506
Wei-Qi Xu https://orcid.org/0009-0000-5675-386X
Shi-Liang Liu https://orcid.org/0000-0001-7556-2575
Ning Yang https://orcid.org/0009-0007-6900-5669
Shuang-Hui He https://orcid.org/0000-0003-4702-3034
All of the data that support the findings of this study are available in the main text or Supplementary Information.